So this would be more of an equity-type structure, which is generally going to be more expensive than debt, or a typical private money lender.My question to everyone is how do I set it up so its a good deal for both of us?

Have you consulted with an architect and/or structural engineer?

The only occasions I used a GC were for structural problems. 

You would be able to decide the market rent, choose the tenant, and execute the lease agreement (depending on the specifics of the retirement structure).

They cannot do anything structural, nor any electrical or plumbing.

As someone who is merely beginning their journey in the world of real estate, I am curious, for someone who has experience, what do you believe are the foundations of a great partnership, and what is the best way to structure them? 

If it is an apartment, they are usually in charge of windows as it is part of the shell of the building and they all need to be the same and meet certain requirements.

What's the commission structure? 

Here's a great article that addresses this from @Kim Lisa TaylorThe main benefit that I've seen folks go for by using LLCs to invest passively is the additional layer of privacy that doing so can offer, if properly structured.

But, if anything, I am trying to use this as an exercise to see if I should have even tried to get this.Assuming the building structure is good and the roof just needs to be resealed, I am just curious what your thoughts are?